Practice Insight, Winter 2021

Practice Insight: Avoiding Confirmation Bias

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Practice Insight explores incidents reported to the College that present learning opportunities for pharmacists and pharmacy technicians. This close up on a complaint highlighted below encourages registrants to recognize and prevent confirmation bias.


A handwritten prescription was presented to a community pharmacy. The pharmacy assistant entered the prescription into the computer system and the pharmacist verified the prescription, including comparing the original prescription against the hardcopy (dispensing record) in accordance with procedures at the pharmacy, before dispensing to the patient. The patient experienced significant symptoms after taking the medication. Upon visiting their physician two weeks later, it was discovered that the patient had been dispensed the wrong medication.


Upon reviewing the complaint, a panel of the College’s Inquiries, Complaints and Reports Committee noted that the pharmacist dispensed the wrong medication after making an error in the interpretation of the physician’s handwriting and that the pharmacy assistant made the same misinterpretation as well when entering the prescription. The name of the intended prescription medication and the name of the medication that was actually dispensed had significant differences in spelling, however they are both generally used to treat a similar medical condition, with a similar strength and dose regimen.

The panel observed that a contributing factor to this error was confirmation bias. They advised that pharmacists must examine each prescription without any assumptions that what has been entered into the system is correct and appropriate for the patient. Any additional checks in the process were rendered ineffective by the confirmation bias.

The pharmacist was reminded that if there is any confusion or lack of clarity relating to a prescriber’s handwriting, then it is their responsibility to contact the prescriber to confirm the prescription. It was the panel’s observation that the pharmacist did not work carefully enough to ensure the accurate dispensing of the medication to the patient.

The panel required the registrant to complete a Specified Continuing Education or Remediation Program, specifically a workshop on medication safety.

The decision of the panel was reviewed at the Health Professions Appeal and Review Board (HPARB) and was upheld. The HPARB panel recommended that the College provide registrants with further information on the issue of confirmation bias.


The Standards of Practice require that pharmacists apply their medication and medication use expertise while performing their daily activities. This includes ensuring that prescriptions received are complete as well as ensuring that a final check of prescribed products is performed. While the exact nature of this final check is left to the judgment of the pharmacy professional and pharmacy, it is essential that the potential issue of confirmation bias is taken into account.

Pharmacy professionals must be aware of the potential for confirmation bias. Confirmation bias is defined as the tendency to see what you expect to see or what you are familiar with, while not looking for information which is contradictory1; it can occur at any point in the medication-use process.2

Handwritten or verbal orders, lack of drug or patient information (i.e. indication for use), similarity in spelling/patterns in naming, and storage location (i.e. storing similarly named medications in close proximity) may contribute to risk of confirmation bias, especially when dealing with look-alike/sound-alike medications2. Additionally, certain technology solutions could contribute to confirmation bias. For example, having the scanned original prescription and the hardcopy side by side on the screen could lead to the copy being read before the original. Drop down lists within pharmacy software often group drugs with similar names in close proximity, which can lead to look-alike/sound-alike mix-ups, as the professional sees the medication they are most familiar with2.

Possible actions that can be taken to reduce confirmation bias include: being aware of similar names, educating pharmacy staff about the potential of confirmation bias, consulting the patient’s medication history to identify potential errors, considering all aspects of the prescription for appropriateness and asking the patient open ended questions about their understanding of the medication they were prescribed1.

The Code of Ethics requires pharmacy professionals to utilize their knowledge, skills and judgment to actively make decisions that provide patient-centred care and optimize health outcomes for patients. If there is any doubt as to the contents of prescription, such as related to a prescriber’s handwriting, it is the obligation of the pharmacy professional to follow up with the prescriber to confirm the prescription.


  1. Pharmacy Connection. Focus on Error Prevention (Summer 2018):
  2. ISMP Canada. ISMP Canada Safety Bulletin Volume 12, Number 9:

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